In an effort to accelerate the acceptance and availability of key mass spectrometric methods to non-traditional users in biomedicine, it is proposed to develop a radically simpler and less costly LC-MS instrument based on a portion of the Hewlett-Packard MSD platform (HP- 5972). This instrument would include both Electrospray and Atmospheric Pressure Chemical ionization methods for compatibility with all classes of samples, and would allow coupling to any liquid chromatography (LC) or Capillary Electrophoresis (CE) apparatus for on-line analysis as well. This instrument would be dedicated to small molecule analysis (700 amu or less), an acceptable range given the overwhelming call for enhanced small molecule analysis in drug development and other fields. Users would find immediate benefit in dealing with a familiar, well developed and mature software environment (HP) Chemstation). A new ES/APCI module with no user variables to adjust will allow routine operation even by novice technicians, providing an Open Access architecture for rugged and robust performance. Previously impractical for technical reasons, the technology which now permits the development of such an instrument has only recently been developed by Analytica and others for more expensive, research oriented MS systems, especially FT-ICR-MS. Migration of this technology to the MSD platform is now possible. PROPOSED COMMERCIAL APPLICATION This platform would provide a high productivity, low cost entry point for both LC and CE users, as well as for GC-MS labs needing the ability to handle non-volatile samples without requiring time consuming derivitization procedures.